The present invention relates to techniques for verifying the source of a signal, such as a signal requesting an operation.
Using PaperWorks.TM. on a PC., Xerox Corporation, 1992, pp. 1-4 and 71-121 describes features of PaperWorks .TM. software. Page 2 indicates that the software stores a document as an electronic image and that a document from a personal computer (PC) can be delivered to a fax machine, whether a document faxed to the PC or a version of a document created on the PC. Page 3 indicates that a user can set a security code and require that it be entered on forms for PaperWorks to process them. Page 73, near the bottom, shows an image of a window entitled "Marketing Reports" within which an image of a name that had been written on a form is shown for a document sent to a PC from a fax machine. Pages 88 and 116 show forms that include a security section. Page 101 shows how to add a security code request to a form; if a form includes boxes for a security code, PaperWorks processes the form only if the correct code has been marked on it. Page 120 explains that one can require entry of a security code on some or all of one's forms to help keep information on one's PC secure. Page 121 shows steps in setting a security code, including typing a code.
Using PaperWorks.TM. from a Fax Machine., Xerox Corporation, 1992, also describes features of the PaperWorks.TM. software. Pages 1 and 4 indicate that information on a PC is secure because one's version of PaperWorks works only with forms created on one's PC; PaperWorks prints a special code on each form so that a document on one's PC can only be accessed with a form from one's PC. Also, for complete security, one can establish a security code to prevent unauthorized use of PaperWorks; that code must be marked on a form before PaperWorks will process it. Pages 5, 15, 32, 35, and 42-43 show forms that include a security section. Page 8 explains that Universal forms are not encoded with a unique PaperWorks ID and can be used with any version of PaperWorks on any PC, but give access only to documents that come with PaperWorks; documents one has stored in PaperWorks or received from others by fax are accessible only with forms encoded with one's unique ID. Page 21 shows a form on which a user can write a name of a document. Page 40 mentions that if a security code is set, PaperWorks processes a starter form only when it's marked with the correct code. Page 41 warns that if the ID of a fax machine one is using is set to a number other than its own number, PaperWorks may send a starter form to a different fax machine, which could give someone unauthorized access to one's PC. Page 42 shows how a PaperWorks security code can be marked on the starter form.